1. As You Come In Get out your unit 1 goal sheet, fill it out and turn it in. Grab Unit 2 notes booklet and the worksheet packet. Review symbols cards with your shoulder partner

2. 9/3 & 9/4 What: You will determine the difference between accuracy & precision; convert using scientific notation & calculate % error How: Review chemical symbols Take symbols quiz Notes WS #1 Chemical symbols Bingo! Homework: Complete WS #1 – worksheets are completion points only!

3. Element Song http://www.youtube.com/watch?v=GFIvXVMbII0

4. If they can learn the elements, why can’t you? http://www.youtube.com/watch?v=GcT qTgBaMQM http://www.youtube.com/watch?v=GcT qTgBaMQM http://www.youtube.com/watch?v=nUc y9eb8cYU http://www.youtube.com/watch?v=nUc y9eb8cYU

5. Unit 2 Chapter 3 Scientific Measurement

6. Daily Challenge The number 602200000000000000000000 is used so frequently in chemistry that it has its own name; Avogadro’s number. What would be a better way of writing it?

7. Scientific Notation To write a number in scientific notation: 1. Move the decimal so that the number is between 1 and 10. 2. The exponent is the number of tens places you moved the decimal 3. Moving the decimal right = - exponent Moving the decimal left = + exponent

8. Examples 65000 m = 0.0000156 s = 0.24 m/s = 6.7 mm = 6.5 x 10 4 m 1.56 x 10 -5 s 2.4 x 10 -1 m/s 6.7 x 10 0 mm

9. To Write a number in Standard Form Change it from scientific notation to a standard number by moving the decimal. The exponent becomes the number of spaces you moved the decimal. Example 1.4 x 10 6 = 1,400,000 2.6 x 10 -4 = 0.00026

10. Adding & Subtracting 1. Change the numbers to the same exponent. 2. Add or subtract the numbers Example: 4.1 x 10 6 + 8.5 x 10 7 0.41 x 10 7 + 8.5 x 10 7 = 8.91 x 10 7

11. Multiplication Multiply the numbers Add the exponents Example: (4 x 10 6 )(2 x 10 8 ) 8 x 10 14

12. Division Divide the numbers Subtract the exponents Example: (9 x 10 7 )/(3 x 10 4 ) 3 x 10 3

13. Try It Out! 1. 3.5 x 10 4 + 5.1 x 10 5 2. (5.7 x 10 8 )(3.5 x 10 6 ) 3. (6.9 x 10 6 )/(4.5 x 10 3 )

14. Answers 1. 5.45 x 10 5 2. 1.995 x 10 15 3. 1.53 x 10 3

15. Or… Use your scientific calculator. The EE button means x10 ^ Do the Try it Out problems again using your calculator and see if you get the correct answers!

16. Accuracy & Precision Accuracy – compare to the CORRECT value Ex: You should have gotten 1 gram of each material in the separation of mixtures lab

17. Accuracy & Precision Precision – compare to the values of two or more REPEATED MEASUREMENTS Ex: Multiple trials

18. Accurate, Precise, Both, Neither? Accurate

19. Accurate, Precise, Both, Neither? Precise

20. Accurate, Precise, Both, Neither? Neither

21. Accurate, Precise, Both, Neither? Precise

22. Accurate, Precise, Both, Neither? Both

23. Accurate, Precise, Both, Neither? Accurate

24. Percent Error Percent Error = |experimental - actual| actual value The absolute value is present so that percent error is always POSITIVE! X 100

25. Example Working in the laboratory, a student finds the density of a piece of pure aluminum to be 2.85 g/cm 3. The accepted value for the density of aluminum is 2.699 g/cm 3. What is the student's percent error? Percent Error = |2.85 – 2.699| 2.699 5.59% X 100 =

26. Try It Out A student takes an object with an accepted mass of 200.00 grams and masses it on his own balance. He records the mass of the object as 196.5 g. What is his percent error? Percent Error = |196.5 – 200.00| 200.00 1.75% X 100 =

27. STOP! Complete Worksheet #1 by next class Worksheets are… A completion grade (i.e. You do not get a grade until it is 100% finished) 10 points on time -2.5 points each day it’s late

28. As You Come In Get out WS #1 to be checked Get out U2 notes booklet Questions from Worksheet?

29. Agenda for 9/5 & 9/6 What: You will identify and round significant figures How: Symbols review Symbols quiz #2 Scientific notation quiz Notes: Sig Figs and Measurement Worksheet #2 Homework: Complete WS #2

30. Units in Chemistry When you add or subtract two numbers, they must have the same units. The answer then has those units as well. Example: 4 m + 12 m = 16 m When you multiply, you also multiply the units. Examples: 4 m x 5 m = 20 m 2 2 g x 3 s = 6g·s When you divide, you also divide the units. Examples: 4 m / 2 s = 2 m/s 8 g / 2 mL = 4g/mL

31. Think about it! What does the word “significant” mean?

32. Significant Figures The numbers that are known, plus a digit that is estimated

33. RULES ***All nonzero numbers are significant*** 125, 689 has 6 significant figures (sig figs) 156 has 3 sig figs 1. Zeros between nonzero numbers are significant. 40.7 mL has ______ sig figs 870,009 g has _____ sig figs 3 6

34. RULES 2. Zeros in front of nonzero numbers are not significant 0.00011 s has _____ sig figs 0.956 g/mL has _____ sig figs 2 3

35. RULES 3. Zeros at the end of a number and to the right of a decimal are significant 85.0000 kg has _____ sig figs 2.00000000 L has _____ sig figs 6 9

36. RULES 4. Zeros at the end of a number are NOT significant. If there is a decimal at the end, they ARE. 2000. m/s has _____ sig figs 2000 m/s has _____ sig figs 4 1

37. EASY RULE! Decimal No Decimal Start at the first nonzero number on the left and count every number right Start at the first nonzero number on the right and count every number left

38. Look at these numbers again 2000. m/s has _____ sig figs 2000 m/s has _____ sig figs

39. Unlimited Significant Figures Counting – There are 23 students in the classroom Could also be expressed as 23.0 or 23.00000000000000 etc. Conversion Factors – 60 min = 1 hour Exact quantities do not affect the process of rounding

40. Try It Out How many sig figs? 1. 0.00125 2. 1.12598000 3. 3,000 4. 0.0100103 5. 5,500. 6. 1.23 x 10 5 3 9 1 6 4 3

41. Rounding Round the following numbers so that they have 3 significant figures: 1. 1.36579 = 2. 120 = 3. 145,256,987 = 4. 0.0001489651 = 1.37 1.20 x 10 2 OR 120. 145,000,000 0.000149

42. Stop Here! You have 10 minutes to work on the front side of WS #2

43. To Multiply & Divide Sig Figs… 1. Count the number of sig figs in each number 2. Round the answer so that it has the same number of sig figs as the number in the problem with the fewest.

44. Example 1 16.19 g / 4.2 mL = 3.8547619 g/mL 16.19 has 4 sig figs 4.2 has 2 sig figs, so the answer should have 2 sig figs 3.9 g/mL

45. Example 2 9.3 m x 0.00167 m = 0.015531m 2 9.3 m has 2 sig figs, 0.00167 has 3 sig figs Therefore, the answer must have only 2 sig figs. 0.016 m 2

46. Try It Out! (1.23)(0.011) = 12.63000/100 = (1.23 x 10 6 )(3.5 x 10 4 ) = 0.0045912/6.570 = 0.014 0.1 4.3 x 10 10 6.988 x 10 -4

47. Stop Complete Worksheet #2

48. Bluff 1A. How many sig figs are in 0.001023? 1B. Solve 456 x 3.2 2A. How many sig figs would the answer have if you calculated 2.1 x 0.01? 2B. How many sig figs are in 123,000? 3A. Solve 2.7 x 3 3B. How many sig figs would the answer have if you calculated 1.4/3.789?

49. Bluff 4A. What is 235,489 rounded to 2 sig figs? 4B. Solve 1/236 5A. Solve 3.7914/9.2 5B. What is 1,926,560 rounded to 1 sig fig? 6A. How could you write 230 with 3 sig figs? 6B. What is 0.00056798 rounded to 4 sig figs?

50. As You Come In Get out WS #2 and have checked for points

51. Agenda 9/9 What: You will apply using sig figs in measurement to a practical lab How: Sig Figs Race Sig Figs Quiz Notes- sig figs in measurement Practical Lab Homework: Complete pages 10 & 11 in notes from your book

52. Sig Figs in Measurements When doing any measurements in chemistry, it is important that you use the correct precision. All measurements should be made by writing all units you know and estimating the last unit.

53. Examples 204060 204060 5454 3838 4810261214 13.9 503010 305070

54. More Examples! 246 0.511.5 204060 3.4 1.16 7272

55. Units of Measurement Every measurement in chemistry MUST HAVE A UNIT! Without a unit, the number means nothing! We will use SI units in class

56. Wrap Up – Clicker! 246 0.511.5 204060 5.3 1.58 4343 5

57. As You Come In Get out your Unit 2 notes, calculator and pencil. Music today will play during review time

58. Agenda 9/10 & 9/11 What: You will calculate conversion problems. How: Mix/Group Review Conversions Notes Work on WS #3 Homework: Try some of the problems on WS #3

59. Review Time Open up your notebooklet to p. 11. Answer questions 1 – 6. Get up and move around the classroom. When the instructor says “group by the answer to #___” you have to form a group of students that is the same as the answer to the problem!

60. Mix/Group How many sig figs: 1. 102.32500 2. 560. 3. 0.0012501 What is the exponent?: 4. 420= 5. 36,000,000 6. 60 =

61. Review Time Now answer questions 7 – 11 on your own. When you are finished, pair up with your face partner and share your answers.

62. Think-Pair-Share Round these numbers so that they have 3 sig figs: 7. 103,250 8. 567.9 9. 0.0012561 10. 100 11. Read the measurement below correctly. 103,000 or 1.03 x 10 5 568 or 5.68 x 10 2 0.00126 or 1.26 x 10 -3 100. or 1.00 x 10 2 204060 4343

63. Challenge Would you be breaking the speed limit in a 40 mi/h zone if you were traveling at 60 km/h? http://www.youtube.com/wat ch?v=Qhm7-LEBznk http://www.youtube.com/wat ch?v=Qhm7-LEBznk

65. Challenge How tall are you in Cheetos?

66. Cheetos conversion

67. Conversion Factors Definition: a ratio of equivalent units It is always equal to 1 When multiplying by a conversion factor, the numerical value is changed, but the actual size of the quantity remains the same

68. Conversion Factors When working with conversion factors, we use the Factor-Label Method (dimensional analysis) The factor is the number that explains the relationship between two things The labels are its’ units

69. Examples 4 quarters = 1 1 dollar OR 1 dollar = 1 4 quarters Factor Label

70. Examples 12 months = 1 1 year 1 foot = 1 12 inches

71. Rules for using Conversion Factors 1. Always start by writing what you know from the problem. 2. Multiply by a conversion factor so that the units cancel out (same unit in numerator and denominator) 3. Continue converting until your answer is in the desired units.

72. Example 1 – your age in minutes Checklist: I started by writing what I knew All units cancel My answer is in minutes

73. Example 1 – your age in minutes 16 years x 365 days 1 year x 24 hours 1 day 60 minutes 1 hour x Checklist: I started by writing what I knew All units cancel My answer is in minutes = 8,409,600 minutes

74. Example 2 How many dollars do you have if you have 38 quarters? 9.5 dollars

75. Example 3 How many nanoseconds are in one week? 600,000,000,000,000 nanoseconds

76. Example 4 How many milligrams are in 12 g? 12,000 mg

77. TRY IT OUT! Now try the next three problems in your notes on your own. Checklist: I started by writing what I knew All units cancel My answer is in desired units

78. The Answers… 1. 790,000,000 seconds 2. 6.71 x 10 3 grams 3. 5.3 x 10 3 mL

79. Still don’t get it? Watch this factor-label method video!

80. STOP! Start Worksheet #3. You must show work and you must use the factor-label method! Remember worksheets are completion grades- no credit until done completely!

81. As You Come In Get out WS #3 and notes Calculate the following problem on the back of your notes: On my last birthday Mrs. Hammond turned 1.23 x 10 9 seconds old. How many years old am I?

82. Agenda 9/12 & 9/13 What: You will calculate density problems. How: Pass the problem review Notes-Density WS #4 Begin Density Lab Homework: Complete WS 4

83. Review Pass the Problem Each student has a problem to solve. The first student will do step 1 (write what you know) and pass the paper to the next student who will complete the second step. Continue passing the paper until you get the answer. Example: How many days are in 60 seconds?

84. Conversion Problem Answers 569 96,400 8 1,000,000

85. Density Review Density = Mass/Volume Volume of liquids is measured in liters or milliliters Volume of solids is length x width x height

86. Do formulas confuse you? Try this visual approach…

87. Example A bar of silver has a mass of 68.0 g and a volume of 6.48 cm 3. What is the density of silver? 10.5 g/cm 3

88. Example A copper penny has a mass of 3.1 g and the density of copper is 8.8571 g/cm 3. What is the volume of the penny? 0.35 cm 3

89. Try It Out What is the mass of a pure silver coin that has a volume of 1.3 cm 3 ? The density of silver is 10.5 g/cm 3. 14 g

90. Using Density as a Conversions Factor What volume of ethanol (in liters) would you have if you acquire 126.56g of ethanol? The density of ethanol is 0.789 g/cm 3. 0.16032 L

91. Try It Out in your notes! The density of apples is 0.641 g/cm 3. If an apple has a mas of 0.089 kg, what is its volume? 140 cm 3

92. STOP! You have 10 min. to work on WS #4

93. As You Come In Get out WS #4 to be checked Complete the Wrap Up on Density on page 15 of your notes. Then list the letters in order of how they would layer out if this were put into a graduated cylinder.

94. Density Review Density = Mass/Volume A – 1.23 g/mL C – 1.28 g/mL D – 1.71 g/mL B – 2.1 g/mL

95. Agenda 9/16 What: You will apply correct measurement techniques and calculate density. How: Conversions & Density Quiz Measurement & Density Lab Homework: Missing Assignments

96. Wrap Up What questions do you have on the lab?

97. As You Come In Get out your Measurement & Density Lab, a pencil and your calculator and your U2 notes Pick up the U2 Test Review

98. Agenda 9/17 & 9/18 What: You will solve density & conversion problems How: Which word am I? Review Complete Measurement & Density Lab Homework: U3 Test Review *U3 Test next block *All missing assignments for when you take your test!

99. Review – Which Word Am I (p. 15 Notes) 1. Mass divided by volume 2. The numbers that are known in a measurement plus one estimated digit 3. How close your measurements are to the true value 4. How close your measurements are to each other 5. Convert 3.69 meters into inches. 6. What is the volume of a cube that has a mass of 7.9 g and a density of 9.45 g/cm 3 ?

100. Answers 1. Density 2. Significant Figures 3. Accuracy 4. Precision 5. 145 inches 6..84 cm 3

101. As You Come In Get out your Unit 2 Test Review to be checked Turn in your Measurement Lab if you haven’t yet!

102. Agenda 9/19 & 9/20 WHAT: You will be assessed on Unit 2 material How: WS Race Take Unit 2 Test Homework: PT Basics Activity (Poster)

103. After the Test PT BASICS HELP